Your car will look "jacked up" as the RD Sport springs in the front will drop the car 1.25", which will look totally out of proportion to the 0.6" drop of the rear Eibach springs. The rake of the car will look weird. (ass end in the air, and front slammed low)

The progressive spring rate difference between the two brands, will also make the car seem like it has a nervous twitch.

I mean the RD Sport's progressive spring rate in the front will be much firmer (stiffer) than the softer Eibach springs in the rear.

That will hurt the overall balance & handling characteristics of the car.

This is exactly why all lowering springs are engineered and sold in matched sets(front and rear 4-spring kits), instead of an assortment of 'mix-n-match' pieces.

Just playing devil's advocate here, but:

If you know what you are doing, and have a specific goal in mind, I don't have a problem mixing and matching. Spring retailers create a set-up based on what they think the average buyer will like. You may not be the average buyer.

I personally like a very stiff front end and a soft rear end (no comments on that please). When I ordered my springs from Ground-Control for the e46, I was able to set them up to my preferences.

However, if you don't know what you are doing, you can end up with a very strange handling car.

If you know what you are doing, and have a specific goal in mind, I don't have a problem mixing and matching. Spring retailers create a set-up based on what they think the average buyer will like. You may not be the average buyer.

I personally like a very stiff front end and a soft rear end (no comments on that please). When I ordered my springs from Ground-Control for the e46, I was able to set them up to my preferences.

However, if you don't know what you are doing, you can end up with a very strange handling car.

+1

This is a great point, but as Joe mentions, it's extremely important to know how different spring rates are going to affect the handling bias of your car. Your safest bet is to go with the package deal.

A completely different thought would be to contact Ground Control as I'm pretty sure they have a "coilover conversion" kit for our cars. Then you can pick whatever ride height and spring rate you want.

haha yea the drop difference is way far apart from front and back, I know RD is over 1 inch, and the rear we got confused with eibachs and here i came to see that its .6 for the rear drop. But i was just curious to see if such a thing was reasonable to do so or even possible.

If you know what you are doing, and have a specific goal in mind, I don't have a problem mixing and matching. Spring retailers create a set-up based on what they think the average buyer will like. You may not be the average buyer.

Yes, but with GC you probably had a linear spring. The RD, Eibach, Dinan, stock are more than likely progressive rates, so it's not going to be the same effect.

Most track guys will run vastly different spring rates, but not on progressive street springs.

Quote:

I personally like a very stiff front end and a soft rear end (no comments on that please).

Quote:

However, if you don't know what you are doing, you can end up with a very strange handling car.

yes.. tons of hopless understeer.

__________________

gone, not forgotten: Viper | Z06 | E90 M3 | E92 335i

Quote:

Originally Posted by Mjolnir

My dog swallowed my FOB. Luckily it was Comfort Access so I could still drive the car. Of course I had to take him with me everywhere and every time he rolled over the windows went down.